Analog Devices Inc. AD774BJNZ

Overview

AD774BJNZ from Analog Devices is a complete monolithic 12-bit successive-approximation analog-to-digital converter with on-chip 10 V reference, clock, and three-state digital output buffers. It supports 0 V–10 V, 0 V–20 V, ±5 V, and ±10 V input ranges, operates from ±12 V/±15 V analog and +5 V logic supplies, and achieves 8 µs maximum conversion time. It is used in precision data acquisition systems requiring direct microprocessor bus interfacing without external support components.

For engineers reviewing the AD774BJNZ datasheet, AD774BJNZ pinout, AD774BJNZ application, or AD774BJNZ equivalent, key selection considerations include its industry-standard AD574A-compatible 28-pin DIP package, 12-bit resolution with ±1 LSB INL (J grade), flexible 8-/12-bit data read modes, and integrated reference stability of 10.00 V ±1% with 10 ppm/°C TC.

Technical Context

The AD774BJNZ implements a SAR architecture with an internal current-output DAC, comparator, and laser-trimmed thin-film resistor network for scaling and bipolar offset. Its control logic supports both full-control mode (using CS, CE, R/C, A0) and standalone mode (triggered by R/C edge), enabling direct integration with 8- and 16-bit microprocessors.

It features on-chip voltage reference buffering (2.0 mA drive capability), programmable input span selection via 10VIN/20VIN pins, and configurable unipolar/bipolar operation through BIP OFF pin routing. All analog and digital grounds are physically separated (AGND at Pin 9, DGND at Pin 15) to maintain 12-bit accuracy under mixed-signal conditions.

Key Specifications

Pinout & Package

AD774BJNZ is housed in a 28-lead plastic DIP (N-28) package with 0.6-inch width and standard through-hole footprint compatible with AD574A layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit SAR ADC applications.

Compared with AD774BJNZ, AD7819BRUZ offers faster speed and lower voltage operation but sacrifices bipolar input and integrated reference, while ADS7800KP provides comparable accuracy with greater reference flexibility at the cost of higher system integration effort and slower conversion.

Availability

AD774BJNZ is available at Aetrix Electronics and suitable for industrial process monitoring, test & measurement equipment, avionics data acquisition, and medical instrumentation requiring stable component supply across commercial temperature grades.

Supply support for AD774BJNZ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, founded in 1965 and headquartered in Wilmington, MA.

The AD774BJNZ belongs to Analog Devices' legacy high-precision SAR ADC product line, designed specifically for industrial and instrumentation applications demanding pin-compatible upgrades to AD574A with improved speed, accuracy, and integration.

FAQ

What is the maximum conversion time specification for AD774BJNZ?

The AD774BJNZ has a maximum conversion time of 8 µs for a full 12-bit cycle, as specified in the Analog Devices AD674B/AD774B datasheet Rev. C. This value applies across the J-grade temperature range (0°C to +70°C) under worst-case supply conditions (+16.5 V VCC, –16.5 V VEE, +5.5 V VLOGIC). The 8 µs figure enables sustained sampling rates above 125 kSPS in time-critical data acquisition systems using the AD774BJNZ.

Does AD774BJNZ require external calibration components?

The AD774BJNZ includes laser-trimmed thin-film resistors for offset, linearity, and full-scale calibration, so external trimmers are optional. For J-grade operation, ±2 LSB unipolar offset and ±0.25% full-scale error are guaranteed without trimming. If higher accuracy is needed, a 50 Ω resistor between REF OUT and REF IN (Pin 8 → Pin 10) suffices for full-scale calibration, and BIP OFF (Pin 12) can be tied directly to AGND (Pin 9) for unipolar use - no potentiometers required for basic AD774BJNZ deployment.

Can AD774BJNZ operate with only +5 V and ground supplies?

No, the AD774BJNZ cannot operate with only +5 V and ground. It requires three independent supplies: +5 V (VLOGIC, Pin 1), +12 V or +15 V (VCC, Pin 7), and –12 V or –15 V (VEE, Pin 11). The dual analog supplies are essential for supporting bipolar input ranges (±5 V, ±10 V) and maintaining linearity across the full 12-bit transfer function. Operating VEE at ground will damage the AD774BJNZ or cause undefined behavior, as confirmed by its Absolute Maximum Ratings table.

How is the 12-bit output data formatted on AD774BJNZ?

The AD774BJNZ outputs left-justified 12-bit data across DB11–DB0, representing the analog input as a fraction of full scale (0 to 4095/4096). Data format is controlled by the 12/8 (Pin 2) and A0 (Pin 4) pins: with 12/8 HIGH, all 12 bits appear simultaneously; with 12/8 LOW, A0 selects whether DB11–DB8 (A0 LOW) or DB3–DB0 (A0 HIGH) are enabled, allowing byte-wide reads on 8-bit buses. The AD774BJNZ does not support right-justified or MSB-first serial formats.

Is AD774BJNZ pin-compatible with AD574A?

Yes, the AD774BJNZ uses the exact same 28-pin DIP pinout as the industry-standard AD574A, including identical signal names, locations, and electrical behavior for CS, CE, R/C, A0, STS, DBn, REF IN, REF OUT, and power pins. This allows direct replacement in existing AD574A-based designs. However, the AD774BJNZ improves upon the AD574A with faster 8 µs conversion (vs. 25 µs), lower power consumption, and tighter initial calibration - all without requiring PCB or firmware changes.